Apparatus for relieving the teeth of circular cutting elements



Aril 3, 1951 R. W. ANDREASSON APPARATUS FOR RELIEVING THE TEETH 0F CIRCULAR CUTTING ELEMENTS 5 Sheets-Sheet 1 Filed March 4, 1948 INVENTOR. 27114699 1/. fllrl 'ewsso/z April 3, 1951 I R. W. ANDREASSON APPARATUS FOR RELIEVING THE TEETH 0F CIRCULAR CUTTING ELEMENTS File d March 4, 1948 5 Sheets-Sheet 2 IN V EN TOR.

April 3, 1951 R. w. ANDREASSON 2,547,345

APPARATUS FOR RELIEVING THE TEETH 0F CIRCULAR CUTTING ELEMENTS Filed March 4, 1948 5 Sheets-Sheet 3 April 1951 R w ANDREASSON 2,547,845

APPARATUS' FOR RELIEVING THE TEETH OF I CIRCULAR CUTTING ELEMENTS Filed March 4, 1948 5 Sheets-Sheet 4 {IL INVENTOR.

27214 0 [7 flfli cq 5.54/2

April 1951 R w ANDR EASSON 2,547,845

APPARATUS FOE RELIEVING THE TEETH 0F CIRCULAR CUTTING ELEMENTS Filed March 4, 1948 5 Sheets-Sheet 5 INVEN TOR. i Jo if M flzz reaaeorz Patented Apr. 3, 1951 UNITED STATES PATENT OFFICE APPARATUS FOR RELIEVING THE TEETH 0F CIRCULAR CUTTING ELEMENTS 9 Claims.

This invention relates broadly to grinding machines and more particularly to a machine of this character which is primarily adapted and pre-eminently suited for backing off or relieving the teeth of rotary cutters such as reamers, milling cutters and the like.

This is a continuation in part application of my copending application, Serial No. 789,456 which was filed December 3, 1947, now abandoned.

An important object of the present invention is to provide a grinding'machine that is exceedingly versatile and capable of performing a wide variety of grinding operations.

Another object of the invention is to provide a grinding machine which is automatic in operation to provide a desired relief for the teeth of cutting elements.

Still another object of the invention is to provide a grinding machine of the above mentioned character which is operable to grind a different relief or clearance on different teeth of a single cutting element.

Yet another object of the invention is to provide a grinding machine that can be easily and quickly adapted for grinding either with or without centers.

A further object of the invention is to provide a grinding machine having a headstock which is uniquely constructed for grinding without 1 centers and which will support relatively long workpieces without excessive overhang.

A still further object of the invention is to rovide a grinding machine of the above mentioned character in which the drive shaft for the center I point of the headstock includes a torsionally yieldableflexible coupling which yields under heavy cuts in a direction to relieve pressure on the grinding wheel whereby to prevent burning of the tool and which permits the tool to assume its proper angular position as soon as'pressure on the work is reduced.

A yet further object of the invention is to provide a grinding machine of the abovennentioned character that isv operative to grind simultaneously end clearance and a predetermined relief on the outside diameter of the work, and which is adjustable to vary either relief independently of the other.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the drawing forming a part of this specifi' cation and wherein like numerals are employed to designate like parts throughout the same,

Fig. l is a side elevational view of a grinding machine embodying the invention and showing the same set up for ordinary circle grinding;

Fig. 2 is a to plan view thereof;

Fig. 3 is an enlarged, fragmentary, side elevational view illustrating the head and tailstock assemblies of the machine, parts thereof being broken away and shown in section;

Fig. 4 is a fragmentary, horizontal, longitudinal, sectional view taken on the line 4-4 of Fig. 3;

Fig. 5 is a fragmentary, vertical, transverse sectional view taken on the line 5-5 of Fig. 3;

Fig. 6 is a fragmentary, top plan view of the grinding machine showing the same set up to relieve the teeth of cutting elements;

Fig. 7 is a transverse sectional view through a cutting element of the type adapted to be acted upon by the machine when the latter is set up as shown in Fig. 6;

Fig. 8 is a fragmentary, top plan view of the grinding machine showing the headstock adapted for grinding without centers and illustrating a typical grinding operation to be performed by this set up;

Fig. 9 is a View similar to Fig. 8 but illustrating a different typical grinding operation;

Fig. 10 is an end elevational View of the workpiece which is shown by way of illustration in Figs. 8' and 9;

Fig. 11 is a perspective view showing a fragmentary portion of the grinding machine and a fragmentary portion of a grinding wheel in operative association therewith, the machine being set up to grind end clearance on a center drill and simultaneously to grind a relief on the outside diameter of the work;

Fig. 12 is a top plan view of the same; and

Fig. 13 is a view showing a fragmentary portion of a grinding wheel in operative association with a center drill workpiece, the grinding wheel being shaped to grind back clearance on the work as well as the grinding operations described in connection with the description of Fig. 11.

The grinding machine shown in the drawing is an improvement over the machine shown in my prior Patent No. 2.389.401 which issued November 20, 1945. Broadly, a headstock 20 and a tailstock 22 embodying the present invention are carried by the usual table 24, and the latter is longitudinally movable inthe conventional manner on a suitable base 26 by handwheel 28. A rotatably driven grinding wheel 3!) is carried by the usual supporting'structure 32 and the latter is movable in the conventional'mann'er transversely on the base 25 and relative to workpiece 34 by a handwheel 36. Preferably, the grinding wheel 30 also is angularly adjustable about a vertical axis on the supporting structure 32.

The tailstock 22 is generally similar to the one shown in my prior patent hereinabove referred to, and comprises a support 38 mounted for angular movement about a vertical axis on a base 40 which in turn is fastened on and movable with the table 24. Angular adjustment of the support 38 is effected by means of a handwheel 42 and the amount of such angular movement is indicated in an obvious manner by reference mark 44 and a scale 46 (Figs. 2 and 3).

Mounted for horizontal sliding movement in the support 38 is a center member 48 which carries the usual center point 50. According to the present invention, however, the center point 50 is mounted on the center member 48 for angular movement about a vertical pivot 52 so that the center point can be angularly adjusted to compensate for angular movement of the support 38 on the base 46. A coil spring 54 behind the center member 43 urges the latter outwardly or to the left as viewed in Fig. 3, and the tension of the spring is regulated by the usual adjusting screw 55. A set screw 58 (Fig. 2) carried by the support 30 extends into a longitudinal slot 60 in the center member 48 and prevents the latter from rotating while permitting free sliding movement thereof axially in the support.

The center member 48 can be readily retracted against the action of spring 54 to release Workpiece 34 by a manually operable lever 62. As best shown in Fig. 2, the lever 62 is pivoted on a supporting arm 64 which is formed integrally on the support 38 and bears against the forward or inner end of the center member.

The headstock 25 comprises a support 66 which is mounted on a plate member I and the latter is carried by a base plate 68 for angular movement about a vertical axis. In the form of the invention here shown, the support 66 is fastened to the plate member I06 by screws 61 so that these members turn as a unit on the base plate 68. The support and plate are held in the selected angularly adjusted position by screws 69 which extend through arcuate slots II in the support and supporting plate member and into the base plate 68. The base plate 68 is suitably fastened to the table 24, and the angular position of the plate member I06 on the base plate is indicated in the usual manner by a reference mark and a scale I2 (Figs. 2 and 3). According to the present invention, a spindle 14 (Fig. 3) is mounted in the support 66 both for rotation about and for reciprocation along a horizontal axis. A relatively deep socket I6 is provided in the inner end of spindle I4; and a draw collet designated generally by the numeral #8, is mounted on such inner end to clamp a Workpiece or other object inserted into the socket. Adjacent the outer or rearward end thereof, the spindle T4 is formed with a radial shoulder which seats a thrust bearing 82, and a coil spring 84 confined between the bearing 82 and an annular shoulder 85 in the support 66 urges the spindle I4 constantly axially to the left as viewed in Fig. 3 without interfering with rotation of the spindle. Axial movement of the spindle M to the left is limited by a radially extending annular shoulder 86 on the drawn collet 18.

A rotary drive for the spindle I4 comprises a horizontal drive shaft 88 which is rotatably supported by a U-shaped bracket 90 formed integrally on the support 66. A motor 92 drives a pulley 94 through a gear reduction unit 96 and the pulley 94 is connected to a second pulley 98 on the drive shaft 88 by an endless belt I00. A gear I02 fixed on the drive shaft meshes with a gear I04 on the rearward end of spindle 14 to transmit motion from the drive shaft to the spindle. In this connection, it will be observed that the motor 92 is mounted on an extension of the supporting plate I06 so that the motor and the support 66 turn as a unit When the supporting plate is adjusted angularly on the base plate 68 in the manner hereinabove described.

Preferably, the drive shaft 88 is formed in two sections. One section of the drive shaft 88 is supported by each arm of the U-shaped bracket 90, and the two sections are selectively connected or disconnected by a clutch I08 which may be of any usual or conventional design and is actuated manually by a suitable handle III]. As a result of this construction, the motor 92 can be operated continuously and the spindle I4 rotated as desired by engaging or disengaging the clutch I08.

Axial movement of the spindle I4 against the action of spring 84 is effected by a cam I I 2, which cam is mounted in a cam support II4 directly behind the spindle and has a vertically disposed, annular cam face which is engaged by one or more cam followers I I 6 carried by and projecting axially from the spindle. In the form of the invention here shown by way of illustration, the cam followers IIG merely comprise metal pins which fit in sockets I I! provided in the adjacent end of the spindle I4 (Figs. 3 and 4). These pins ride on the cam face during rotation of the spindle I4 and, by following the contour of the cam I I2 impart a reciprocating motion to the spindle.

Preferably, an annular series of sockets II! is provided in the end of spindle I4 so that any desired number of pins H6 can be provided and so that the pins can be arranged in any suitable angular relation around the spindle. Also, the sockets II'I preferably are provided with radial set screws I I8, which are adapted to be tightened against the pins II6 to hold the latter fixedly associated with the spindle I4.

The cam I I 2 shown in Figs. 1-5 has an annular cam face all of which lies in a single plane except for an axially offset or recessed segmental portion IIEl. Also, in these figures of the drawing a single pin HE is shown in the gear I04. This arrangement causes the spindle I4 to advance axially each time the pin IIE rides out of the recessed portion H9 and to remain in the advanced position until the pin again rides down into the recessed portion. Thus, the spindle I4 is caused to advance and retract once for each revolution of the gear I04. This motion is suitable for grinding many types of cutting elements.

It is a feature of this invention that the cam support H4 is independently, angularly adjustable about a vertical axis so that the cam face may be cooked at an angle with respect to the adjacent end of spindle T4 to control the length of the reciprocatory motion imparted to the spindle. To this end, the cam support H4 is mounted on a suitable plate member I 20, and screws I22 extend downwardly into the plate through arcuate slots I23 provided in the base of support II 4 (Fig.2). A reference mark I26 on the plate I25 cooperates with a scale I28 on the tongue I38 on. the front bracket section H32. pivot pin Ml) extends through the bifurcations support IM to indicate the angular setting. of the'sup'port. In this connection it will be noted .(Fig. .3), that the scale I23 is disposed .on both ,sidesof the zero mark to indicate the angular position of cam support II when the latter is turned eitherto the right or to the left of neutral position. When both supports t6 and iii are at zero reading on their respective scales l2 and I28, the cam H2 is disposed in axial alignment with .the spindle: i4 and the latter is disposed in axial alignment with the center point of tailstock 22. The plate member 5 2% is fastened to the base .plate 68 by screws I ZI, and the latter extend through transversely elongated slots 523 which lpermit adjustment of the cam support He latter-ally .on the machine.

For certain types of grinding without centers, the workpiece can be mounted directly in the -.'spindle I4 and clamped tightly by the draw collet .18. in the. manner hereinabove described. How- .ever, for other typesof grinding without centers or for grinding between centers, an additional at.- tachment is required which'is now described in :The center unit for headstock 2%? comprises a :mounting bracket having swiveled sections I88 and I32. As best shown in Fig.3, the rear bracket section E33 is formed with a shank 34 which is adapted. to be received insocket l5 and to be tightly clamped by draw collet I8. At its forward end; the rear bracket section are is provided with bifurcations I36 which embrace projecting A 4.36 and tongue lfiii to complete the swivel con.- .nection. In practice the attachment is positioned as shown in the drawing with the pivot Mii dis- .posed vertically with respect to the table- 24 so -that the front bracket section I32 can swing in a horizontal plane. about the pivot.- A center point MZ'is mounted for rotation in the front bracket section I32g and, when the parts of the .machine are positioned as shown in F-igs. 1-5

.of the drawing, the center point 542 is'in axial alignment with the corresponding center point 58 of .tailstock 22.

'In order to rotatably drive the center point I42, a driven shaft is journaledfor rotation in upwardly extending arms I44 and M5 which are :formed integrally on respective bracket sections I and I32, and the driven shaft is connected to the center point I42 through spur gears Mil and IE9. As perhaps best shown in Fig. 3, the driven shaft comprises two. separate axially aligned. sections I52 and I54 which are journaied in arms 7 I44 and M3 respectively. The rear terminal portion of shaft section it? is removably received in asocket provided in the forward end of drive shaft 88. .Any suitable connection such as. a key or spline may be providedbetween the drive and driven shafts to establish a direct rotary drive therebetw een-but permit the driven shaft to be ber or the like. This construction provides a con- 7 stant velocity drive for the center point I42 regardles'sjof the angular position of the front bracket section I32 about pivot I58. Also, an additional and perhaps even more important result is achieved in that the coupling I58 will yield under heavy cuts in a direction to relieve pressure on the grinding wheel 39 whereby to prevent burning of the tool or work 34. Further, as pressure against the work .35 is reduced, the torsionally flexed coupling I58 causes the work to catch up to the proper angular position for the required operation.

Any suitable form of driving connection may bev employed between the center point I42 or gear Itifi and the work 3 3. For the purpose of illustration, I have here shown a conventional dog I59 fastened to the gear I laterally of center point hi2, which dog projects forwardly past the center point and engages a radially'projectingbracket I 52 mounted on the adjacent end of the tool '34 and reinovably fastened thereto 164.

When the center attachment is employed on the headstock 2e it is necessary to disengage the driven gear lee from spindle it, since it obviously is not intended for the spindle to rotate the mounting bracket I36, E32. As shown in Fig. 4, the gear 554 is mounted on an axially projecting shank E at the rearward end of spindle It, and w the inner annular marginal portion of the gear to hold the latter on the shank. Preferably, the

head ITZ is countersunk to extend flush with the outer face of the gear 5%, as clearly shown in the drawing. Also, a screw iii is threaded into the gear ili l beside the center screw Iifi and the head of screw I'M is received in a peripheral notch provided in the head ilZ. When screw :14 is threaded into the gear It' l, it transmits rotation from the spindle E4 to the gear through screw IEE! in an obvious manner. However, when screw Il is removed, the gear I34 is free to rotate on the shank its independently of spindle it. When the machine is adapted for center grinding as shown in .Figs. 1-5, the screw I'M is removed so that drive shaft 88 simultaneously rotates gear IM and center point I 42 without rotating the spindle I i. On the other hand, when the machine is set up for grinding without centers, the center point unit is removed from the spindle I I, the, tool is clamped in the spindle b draw collet I8,- andscrew I14 is inserted to lock the gear I84 to thespindle. 'When the part are thus assembled, the drive shaft 88 acts through gears I02 and I04 to rotatably drive the spindle Wand consequently the tool carried thereby in'the manner hereinabove described.

. As, suggested, a primary feature of the instant grinding machine. resides in its versatility and in its adaptabilit for performing different types tomanufacturers. This is particularly true when it is considered that grinding machines of this type are relativelyexpensive.

The arrangement of the cam II 2 behindthe by a set screw spindle I4 is productive of new and beneficial results. By positioning the cam H2 in this manner, the spindle 14 can be made of large'diameter and relatively long so as to easily accommodate and solidly support relatively long work pieces. Heretofore, when grinding without centers, it has been difficult to operate on long workpieces since in most instances the latter could not be fastened to the head chuck without excessive overhang. If the work extends too far out of the chuck, vibrations are set up during grinding which cause destructive chattering to occur, and the result is a poor if not faulty grinding operation. As a result of the instant construction, however, the spindle 14 can be made sufliciently long to accommodate any usual or conventional size of work and the work can be set far enough back into the spindle to eliminate the excessive overhang which so often is responsible for poor work and faulty operation. The collect chuck I8 grips the workpiece solidly at the oint where it projects from the headstock and holds the same properly for th grinding operation. At the same time, axial manipulation of the spindle and consequently of the workpiece can be readily achieved.

In Figs. 1-5 the machine is shown set up for ordinary circle grinding. The workpiece 34 is mounted between the center points 50 and I42 and the screw I'M is removed to release gear I04 from spindle 14. When clutch III} is operated to engage the two sections of drive shaft 88, gears I02 and I48 rotatably drive gears I04 and I50 respectively and the latter gear rotatably' drives the workpiece 34.

Ordinarily, in this type of grinding it is desirable to merely rotate the workpiece without reciprocation, and no reciprocation of the spindle 14 or workpiece 34 will occur if all of the pins H6 are removed from the gear I04, if cam II 2 is removed from the support I I4, or if a no cam type of cam is employed and arranged in axial alignment with the spindle.

On the other hand, it may be desirable at times to reciprocate the work simultaneously with the grinding operation. In this connection, it will be readily apparent that any desired reciprocatory movement of the workpiece 34 may be effected by employing a cam H2 in which the cam face has the necessary predetermined rise and fall in combination with a suitable number and arrangement of pins I I6.

Automatically backing off or relieving the teeth of cutting tools such as the reamer I78 shown by way of example in Fig. 7 is a typical example of a grinding operation in which the work is simultaneously rotated and reciprocated. To perform this type of operation, the workpiece is mounted between center points 50 and M2 and the machine is set up as shown in Fig. 6. Specifically, the tailstock support 38 and the headstock mounting plate I06 are angularly adjusted a predetermined number of degrees in the same direction. In the drawing (Fig. 6), both the headstock and the tailstock are shown adjusted 10. Angular adjustment of the headstock and the tailstock in this manner brings the center support 48 and the spindle I4 at a corresponding angle with respect to the longitudinal axis and direction of travel of the table 24. The tailstock center point 50 is then swiveled in a direction to compensate for the angular adjustment of the support 38, and the headstock mounting bracket 32 is similarly swiveled in a direction to compensate for angular movement of the base plate I05. This adjustby the center points properly at right angles to the working face of grinding wheel 30. The plate I20 which mounts the cam support II4 on base plate 68 is then adjusted transversely on the latter to center the cam I I2 properly with respect to the adjacent end of spindle I4.

A no cam type of cam H2 is employed, and the cam support I I4 is adjusted angularly on the supporting plate I20 to cook the cam face angularly with respect to the confronting face of gear I04. The reamer I18 here shown byway of illustration has six longitudinal cutting teeth I82, and six pins II6 are provided in equispaced relation around the gear I04.

When the parts of the grinding machine are arranged as described above, rotation of gear I04 will cause the pins I I6 to rotate on cam I I2; and, due to its cocked position with respect .to the gear, the cam will cause the spindle to advance axially a predetermined distance each time a pin IIG traverses the portion of the cam face disposed nearest the gear. Thus, although the entire cam faces lies in a single plane the portion nearest the gear I04 becomes a high point on the cam. As each pin I I6 rides upwardly on the high point of the cam I I2, the spindle I4 advances against the action of spring 84 and as each pin rides downwardly away from the high point the spindle retracts. From the foregoing, it will be readily apparent that the spindle 14 will continue to retract until the next adjacent pin H6 begins to ride upwardly on the high point of the cam face. Manifestly, the amount of axial movement imparted to the spindle 14 will vary according to the angular position of the cam face. As the spindle I4 moves back and forth in support 66, it reacts through the workpiece 34 to impart a similar reciprocatory motionto the tailstock support 48 which in turn reciprocates back and forth against the action of spring 54.

From the above it will be readily apparent that, due to the angular position of the center member 48 in tailstock 22 and of the spindle I4 in headstock 20 with respect to the longitudinal axis of the table 24, reciprocation of the center member and spindle will move the workpiece 34 back and forth with respect to the working face of grinding wheel 30. Since the center member 48 and spindle I4 are disposed in parallel relation with respect to each other, this movement is accomplished without affecting the engagement of either center point with the work. Thus, the instant arrangement causes the workpiece to move to ward and from the grinding wheelsix times during each revolution of the'work 34.

7 By properly positioning the workpiece 34 angularly on the centers 50 and I42, the work can be brought into engagement with the grinding wheel immediately behind the cutting'edge I84 of each tooth I82. From this point, the work is fed toward the wheel 30 so that the latter grinds progressively more material from the tooth to provide progressively increasing clearance or relief on the surface I86 behind each cutting edge as shown in Fig. 7

After grinding each tooth I82, the machine automatically retracts the workpiece 34 away from the grinding wheel 30 until the next adjacent tooth I82 moves into grinding position at which time the machine automatically advances the workpiece against the wheel to repeat the i operation.

It will, of course, be apparent that the distance the workpiece 3 1 ismoved toand from the-grindin'g wheel 35-canbe= controlled. either by angularly adjusting'the center supports Standtfi or byangularly adjusting the cam'support H4.

By mounting the-cam support IM; so that the cam"! [2 also can be adjusted to control the movement of the workpiece in the above manner several advantages are obtained. For example, this feature is important when relieving two or more axialcutting edges on a workpiece where it is necessary or desirable to provide a, different clearance for each tooth. In this case, the various clearances can be provided merely byadjusting the cam angularly about its vertical axisbetween two positions corresponding with the desired clearances; and it is'unnecessary to disturb the position ofthe center supports or to remove the workpiece from the machine while making the adjustment. I 7

:Also, the machine can bemade to grind either rightehand or left-hand relief merely by adjusting the cam .angularly either to they right or to the left of neutral position. As a result of the instantarrangement of parts, no other adjustment is necessary in order to produce this result.

. In general, a no cam type of cam can housed in any case where the clearance or relief to be ground is 180 or less. Thus, for most types of grinding operations only one cam is necessary since its rise-and fall can be varied merely by adjusting it angularly about a vertical axis in the manner described. If a clearance or relief greater than 180,is to be ground, a cam having rise and fall must be provided. However, in practically every other case, a no cam type of cam can be adapted for the purpose at hand.

Figs. 8, 9, and 10 illustrate still another set up for the machine. In this case the machine is adapted for grinding without centers and a workpiece designated generally by the numeral 58 is mounted directly inthe spindle i i in the manner hereinabove described. In the set up here shown, the support $6 is positioned at zero reading on the scale 12' so that the axis of the spindle is parallel with the longitudinal axis of the table 24. clearance or relief to be ground on the workpiece 813 is less than 180 so that a no cam type of cam can be used... The support I ie which carries the cam H2 is adjusted angularly on the plate .126 to cook the cam face at an angle with respect to the adjacent end of the spindle (Fig. 8) As shown in Fig. 10, the workpiece E83 here shown by way of illustration has two cutting teeth and clearance is to be provided for each tooth. Consequently, two pins lit are provided 186 apart on the gear 564. When grinding the upper shoulder I92 of the workpiece 188, the grinding wheel 3!) is mounted at an angle corresponding to the angle of the shoulder as shown in Fig. 8. Thus, the workpiece ifiii will be reciprocated twice during each revolution thereof; and, if the workpiece is properly positioned angularly in the chuck it, it will engage the grinding wheel 39 immediately behind the cutting edge and be fed progressively against the wheel as the surface of the workpiece behind the cutting edge moves across the face of thewheel. After each tooth passes the wheel 30,-the workpiece l88 is automatically retracted so that the workpiece does not again'e-ngage the wheel until the cutting edgeief the next tooth has moved past the wheel. The operation is repeated for each tooth of the cutting .elementanrl-the entire sequence of operaticniis automatic... .1 .1. i i

The same set up may be used to grind a point I94 on the workpiece I88, as shown in Fig. 9.

In Figs. 11' and 12, I have shown a machine of slightly modified construction, which machine drill is a typical workpiece requiring this type;

of grinding operation, and a workpiece of this character is shown in the machine. The center drill l92 here shown has two cutting flutes (Fig. 10). The machine is set up to grind a relief on each land of the center point 1% and simultaneously to grind an end clearance on the tapered shoulder M38. The particular grinding operation here. under consideration requires a grinding wheel which is dressed or shaped to complement the profile cf the workpiece defined by the center point I96 and the shoulder Mil. Thus, the grinding wheel at here shown has a flat annular peripheral surface 289 which engages the periphery of center point use and an adjacent tapered annular surface 262 which engages the shoulder 198.

In the grinding operation here under con sideration, only the headstock portion of the machine is used and the center point adapter unit is attached thereto for operation in the manner hereinabove described. However in this form of the invention, a collet chuck 2M is carried by the gear H58 in place of the center point M2. As clearly shown in the drawing, the workpiece i912 is mounted in the collet chuck 2M and is v rotatably driven by the gear 55% in an obvious manner. Except for the diiference in construction specifically referred to above, both the head stock and the center point adapter unit are identical to theco'rresponding mechanisms described in detail in the foregoingportion of the specification.

To set up the machine, the headstock support 66 is adjusted angularly by loosening bolts 69 and moving the supporting plate N36 to the desired angular position as indicated on the scale 12. The screws as are then tightened to hold the headstock support 56 and supporting plate H16 in the selected adjusted position. After the above adjustment has been made, the front bracket portion i3? is moved angularly with respect to the rear bracket portion I36 an equal amount in a reverse direction so that the longitudinal axis of workpiece H92 is parallel with the table 24. The cam support H6 is similarly adjusted angularly in order to impart a reciprocating motion to the workpiece. This operation is effected by loosening the screws H2 and angularly adjusting support lie on plate i2ii, the screws 22 are then tightened to hold the cam support lid in the selected adjusted position. The grinding wheel 3% is then positioned on the machine so that the grinding surfaces 20d and 282 properly engage surfaces tit and I93 respectively of the workpiece E92.

Adjustment of the headstock support deter-, mines primarily the amount'of relief which will be ground on the outside lands of the center point I96, and adjustment of' the cam support lltl determines the amount of end clearance to be ground on the shoulder 98; In the present set-up, a no cam type of cam may be used and the gear MM is equipped with two pins M5 disposed apart and properly correlated angularly with respect to the cutting flutes of the workpiece as described in connection with the description'of Figs. 8, 9, and 10. It will be readily apparent however that other types of cams and a different pin arrangement may be conveniently or necessarily employed when other types of cutting tools or other workpieces are being ground.

When the machine is set into operation by actuation of handle H to engage clutch I08, workpiece I92 is continuously rotated and simultaneously reciprocated by engagement of pins I IS with the cam I I2. As suggested, the amount of movement of the workpiece back and forth relative to the cutting surfaces of the grinding wheel 3!] depends primarily upon the angular setting of plate I06. Consequently, the amount of clearance which will be ground on the outside diameter or lands of the center point l96 will depend upon the angular position of the support 66 and plate I06. On the other hand, the amount of axial movement between the workpiece I92' and the grinding wheel 30 is determined primarily by the angular position of the cam support I [4. Consequently, the amount of end clearance provided for on the shoulder i953 will depend primarily upon the particular adjusted position of the cam support. From the foregoing, it will be readily apparent that at the O. D. relief and the end clearance will be ground simultaneously and that these separate grinding operations may be individually controlled by one or the other of the adjustments referred to above.

In addition to the above, a desired amount of back clearance can be provided on the center point I96 by dressing the wheel 30 so that the cutting face 290 thereof engages the center point as shown in Fig. 13. When the grinding wheel is dressed in this manner, a radial relief can be ground on the lands of the cutting flutes, end clearance can be ground on the shoulder 98, and back relief provided for the center point. All three of these grinding operations are made simultaneously and each operation can be separately controlled either by dressing the cutting surfaces of the grinding wheel to the desired shape or by adjusting some part of the machine.

It is to be understood that the forms of the invention herewith shown and described are to be taken as preferred examples of the same and that various changes in the size, shape, and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the appended claims.

Having thus described the invention, I claim:

1. In a grinding machine, a headstock having a rotatable and reciprocable driving spindle, and a spindle support mounted for angular movement about an axis normal to the axis of rotation of said spindle; means for rotatably driving said spindle; a cam axially behind said spindle; cam follower means rotatable and reciprocable with the spindle and engageable with said cam; a carrier for said cam adjustable about an axis normal to the axis of rotation of said spindle; and a mounting for said carrier mounted for sliding adjustment in a direction normal to the axes of both the carrier and of the spindle.

2. In a grinding machine, a headstock comprising a supporting bracket having swiveled sections; work mounting means rotatably carried by one section of said bracket; a rotatable shaft having two axially spaced sections carried by respective sections of said bracket, one of said shaft sections having a driving connection with. said work-mounting means; and a tor- 12 sionally yieldable, flexible coupling connecting the two sections of said shaft.

3. In a grinding machine, a headstock having axially spaced shafts; a torsionally yieldable, flexible coupling connecting said shafts; a pair of swiveled members each rotatably supporting a respective one of said shafts; a center point for supporting one end and rotatably driving a workpiece to be ground rotatably carried by one of said members; means rotatably connecting said center point to one of said shafts, the parts so constructed and arranged that said flexible coupling permits angular adjustment between said shafts when one of said members is swiveled relative to the other and whereby said coupling will yield under heavy cuts in a direction to relieve pressure on the grinding wheel to prevent burning of the work; drive means; and clutch means connecting said drive means to the shaft remote from said center point.

4. In a grinding machine, a headstock comprising a support; a spindle journaled for rotation in said support; a pair of pivotally connected brackets, one of said brackets removably fastened to the spindle; work-mounting means in the other of said brackets; and drive means including a pair of shafts each journaled for rotation in a respective one of said brackets, a torsionally yieldable, flexible coupling connecting said shafts, and means for transmitting motion from said shafts to said work-mounting means.

5. In a grinding machine, a headstock comprising a support; a spindle journaled for rotation in said support; a pair of pivotally' connected brackets, one of said brackets removably fastened to the spindle; work-mounting means in the other of said brackets; and drive means including a pair of shafts each journaled for rotation in a respective one of said brackets, a torsionally yieldable, flexible coupling connecting said shafts, means for transmitting motion from said shafts to said work-mounting means, gear means driven by said shafts for rotatably driving said spindle, and means for rotatably disconnecting said gear means from the spindle.

6. In a grinding machine, a headstock including a rotatable spindle; rotatable drive means; means for selectively connecting said rotatable drive means to the spindle, whereby said drive means can be utilized to rotatably drive the spindle or disconnected therefrom; and an adapter unit including support means detachably associated with and carried by the spindle, work-mounting means rotatably carried by the support means, a driven shaft detachably connected to the drive means, and means for transmitting motion from the driven shaft to said work-mounting means.

7. The combination as set forth in claim 6 wherein said support means comprises two pivotally connected bracket sections, and wherein said driven shaft comprises two shaft sections connected by a torsionally yieldable, flexible coupling, each of said shaft sections being rotatably supported by a respective one of said bracket sections.

8. In a grinding machine, spaced supports mounted in proximity to each other and each independently, angularly adjustable about a vertical axis; a cam carried by one of said supports having a vertically disposed annular cam face; a rotatable and reciprocable spindle assembly carried by the other of said supports disposed in horizontal alignment with said cam and with 13 one end thereof in spaced, confronting relation with respect to said cam face; cam follower means carried by the spindle assembly and engageable with said cam face during rotation of the assembly; resilient means urging said spindle assembly in the direction of said cam; a horizontally adjustable base carrying said cam support; drive means; means for selectively connecting said drive means to the spindle assembly, whereby said drive means can be utilized to rotatably drive the spindle assembly or disconnected therefrom; and an adapter unit including support means detachably associated with and carried by the spindle, work-mounting means rotatably carried by the support means,

a driven shaft detachably connected to the drive means, and means for transmitting motion from the driven shaft to said Work-mounting means.

9. The combination as set forth in claim 8 wherein said support means comprises a pair of pivotally connected sections, and wherein said driven shaft comprises a pair of shaft sec- 14 tions each rotatably supported by a respective one of said support sections; and a torsionally yieldable, flexible coupling connecting the two sections of said driven shaft.

RUDOLF WILLIAM ANDREASSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,806,562 Pickler May 19, 1931 2,325,364 Boening July 27, 1943 2,363,482 Clarke Nov. 28, 1944 2,389,401 Andreasson Nov. 20, 1945 2,434,753 Andreasson Jan. 20, 1948 FOREIGN PATENTS Number Country Date 518,625 Great Britain Mar. 4, 1940 

